The long-term objective of this research is to develop a cell-based system for delivering therapeutic gene products to brain and spinal cord. Several candidate protein pharmaceuticals exist whose use for treatment of genetic or other CNS disorders is severely hampered by the absence of a convenient delivery mechanism. A stable cell-based delivery system for such therapeutics could bypass the almost prohibitive clinical requirement for multiple intracranial injections of molecules that may often be expensive to obtain at the required levels of purity. A successful cell-based delivery system requires two problems to be solved. First, a population of cells must be identified that, when transplanted into the adult CNS, will migrate, integrate efficiently, and survive in diseased tissue. Based on preliminary rodent studies, it appears that Q Therapeutics' patented glial precursor cells, conveniently obtained from adult or embryonic tissue, overcome this problem. Second, an expression technology must be devised that bypasses problems associated with currently available forms of gene therapy including toxicity, side effects associated with inappropriate integration sites, and transgene silencing. This Phase 1 SBIR proposes to establish such a technology. [unreadable] [unreadable] Homologous recombination based integration of transgenes downstream of strong promoters, if successful in glial progenitor cells, will allow targeted transgene integration without additional vector sequences that are likely to be the source of several problems with current gene therapy vectors. Research proposed here will establish the feasibility of homologous recombination in glial progenitor cells and expression of integrated transgenes after transplanation into rodent hosts. The first anticipated target of this therapeutic strategy is Battens disease, a heritable lysosomal storage disease that results in strong neurological phenotype in infants. If successful, this will establish the feasibility of a novel therapeutic strategy to combat several highly prevalent neurological diseases. [unreadable] [unreadable] [unreadable]